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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
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To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

32590 results found.

  1. GRB 251103A: WFST optical observations
  2. EP251102a: update of EP-FXT follow-up observation
  3. EP251102a: OHP/T193 optical observations
  4. GRB 251103A: OHP/T193 optical observations
  5. GRB 251103A: Xinglong 2.16m optical detection
  6. GRB 251103A: Insight-HXMT detection
  7. GRB 251103A: KAIT optical observations
  8. GRB 251103B: Nanshan/HMT optical upper limit
  9. GRB 251013C: 7DT detection and Medium-band SED of Afterglow
  10. GRB 251103B: MITSuME Akeno optical upper limits
  11. Fermi GRB 251103A: Global MASTER-Net observations report
  12. LIGO/Virgo/KAGRA S251103f: Identification of a GW compact binary merger candidate
  13. EP251102a: NIR observations with WINTER
  14. GRB 251103A: J-band detection with WINTER
  15. Swift GRB 251103B: Global MASTER-Net observations report
  16. GRB 251103B: GROWTH-India Telescope optical upper limits
  17. GRB 251103A: Kilonova-Catcher optical afterglow detection
  18. GRB 251103A: Swift/UVOT Detection
  19. GRB 251103A: Fermi GBM Observation
  20. GRB 251103A: SVOM/GRM observation
  21. GRB 251103A: Swift-XRT afterglow detection
  22. LIGO/Virgo/KAGRA S251031cq: Updated Sky localization
  23. GRB 251103A: SVOM/COLIBRÍ (FM-GFT) optical observations
  24. EP251102a: Einstein Probe detection of a fast X-ray transient
  25. GRB 251025B: OHP/T193 optical upper limit
  26. EP251102a (WXT 11900459650): LCO observations confirm COLIBRÍ candidate
  27. GRB 251103A: LCO optical observation
  28. GRB 251103A: GOTO optical afterglow detection
  29. GRB 251102A: AstroSat CZTI detection
  30. GRB 251026A: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical counterpart
  31. GRB 251103A: NOT spectroscopic redshift z = 0.76
  32. GRB 251103A: LCO optical afterglow detection
  33. GRB 251103A: NOT optical afterglow candidate (duplicate submission)
  34. GRB 251103A: NOT optical afterglow candidate
  35. Fermi GRB 251102A: Global MASTER-Net observations report
  36. GRB 251031A: Fermi GBM Observation
  37. LIGO/Virgo/KAGRA S251031cq: Identification of a GW compact binary merger candidate
  38. GRB 251031A: Swift/BAT-GUANO localization skymap of a burst
  39. Konus-Wind detection of GRB 251028A
  40. GRB 251025C: SVOM/GRM observation
  41. GRB 251028A: GECAM-B detection
  42. GRB 251028A: SVOM/GRM observation
  43. IceCube-251025A: Two Transient Candidates from the Zwicky Transient Facility
  44. GRB 251028A: Fermi GBM Observation
  45. GRB 251026B: SOAR Classification of GOTO25jgl/SN2025absf as a Type Ia supernova
  46. GRB 251022A: Swift-XRT confirmation of fading
  47. GRB 251026B: LBT near-infrared observations
  48. GRB 250926B: VZLUSAT-2 detection
  49. GRB 250926A: VZLUSAT-2 detection
  50. GRB 250925A: VZLUSAT-2 detection
  51. GRB 251026A/EP251026a: SVOM/VT optical counterpart
  52. GRB 251026A/EP251026a: EP-FXT follow-up observation
  53. GRB 251028B: Fermi/GBM observation
  54. GRB 251028B: Swift/BAT-GUANO localization skymap of a burst
  55. GRB 251028B: Glowbug gamma-ray detection
  56. GRB 251028A: Glowbug gamma-ray detection
  57. GRB 251028B: CALET Gamma-Ray Burst Monitor detection
  58. Fermi GRB 251028B: Global MASTER-Net observations report
  59. GRB 251025B: GROWTH-India Telescope continued multiband optical observations and rebrightening
  60. GRB251026B: PRIME H-band upper limit
  61. GRB251025B: 3.6m DOT Optical Observations
  62. SVOM trigger sb25102702/GRB 251027A is not a GRB
  63. IceCube-251025A: Upper limits from a search for additional neutrino events in IceCube
  64. GRB 251025B: Swift-XRT confirmation of fading
  65. GRB 251013C : 3.4-m telescope of Iranian National Observatory (INO340) optical observations
  66. GRB 251026B: Swift-XRT observations of GOTO25jgl/AT2025absf
  67. GRB 251025C: Glowbug gamma-ray detection
  68. Fermi-LAT Gamma-ray Observations of IceCube-251025A
  69. GRB 251023B: Swift-UVOT Upper Limits
  70. Konus-Wind detection of GRB 251022A
  71. GRB 251022A: SVOM/GRM observation
  72. GRB 251026B: Swift ToO observations
  73. GRB 251026A/EP251026a: Einstein Probe detection of a fast X-ray transient
  74. GRB 251027A: LCO optical upper limit
  75. GRB 251027A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  76. GRB 251017A: Mondy AZT-33IK and Koshka Zeiss-1000 optical observations
  77. GRB 251023B / EP251023b: Mondy optical upper limit
  78. GRB 251017A: INASAN-Kislovodsk optical observations
  79. GRB 251026A: Mondy optical upper limit
  80. GRB 251025B: Mondy optical observations
  81. GRB 251025B: Kilonova-Catcher optical afterglow detection
  82. Konus-Wind detection of GRB 251016A (short/hard)
  83. GRB 251025B: VLT/MUSE spectroscopic redshift z = 2.003
  84. GRB 251026B: Tentative GOTO optical counterpart candidate
  85. GRB 251025C: AstroSat CZTI detection
  86. EP251023a: Mondy optical observations
  87. GRB 251025C: CALET Gamma-Ray Burst Monitor detection
  88. GRB 251025B: MAO/AZT-22 optical observations
  89. LIGO/Virgo/KAGRA S251026bn: Updated Sky localization
  90. Fermi GRB 251026B: Global MASTER-Net observations report
  91. Fermi GRB 251025C: Global MASTER-Net observations report
  92. LIGO/Virgo/KAGRA S251026bn: Identification of a GW compact binary merger candidate
  93. GRB 251026A: Swift-XRT observations
  94. GRB 251025B: OHP/T193 optical detection
  95. GRB 251025B: J-band detection with WINTER
  96. GRB 251026A: SVOM/C-GFT upper limit
  97. IceCube-251025A: DDOTI Optical Upper Limit
  98. GRB 251026A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  99. GRB 251025B: SVOM/VT optical bump
  100. GRB 251025B: SVOM/COLIBRÍ (FM-GFT) strong rebrightening of the optical counterpart

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